export interface ImgTag {
    /** Full match of the <img> tag */
    fullMatch: string;
    /** Value of the src attribute */
    src: string;
    /** Value of the alt attribute (undefined if missing) */
    alt: string | undefined;
    /** Whether the tag has an alt attribute at all */
    hasAlt: boolean;
}
/**
 * Extract all <img> tags from an HTML string.
 */
export declare function extractImgTags(html: string): ImgTag[];
/**
 * Replace an <img> tag's alt attribute in HTML, or add one if missing.
 */
export declare function setImgAlt(html: string, imgTag: ImgTag, altText: string): string;